SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Protorthis porcias Walcott Feet Meters 



Cyrtolitcs mystcs Walcott 



Agnostus sp. 



Hystricurns briscocnsis n. sp. 



Hystricurus cinctus n. sp. 



Hystricurus dorsatus n. sp. 



Hystricurus venustus n. sp. 



Symphysurtna 3 sp. 



Kingstonia sp. 

 The base of 3 is an arbitrary line selected owing to the 

 presence of a fault having a hade of 50° north 25° east. 

 The displacement of the beds is not great although the 

 layers are upturned and more or less contorted on the 

 southwestern side. (See pi. 6.) Comparing the section 

 with tlie Stoddart-Dry Creek section 5 miles (8 km.) 

 to the south it is probable that about 250 feet (76.2 m.) 

 of strata have been duplicated by the fault. 

 3a. Strata duplicated by fault, estimated, 250 feet (76.2 m.). 

 3b. Layers of limestone varying in thickness from one or two 

 inches (2.5 or 5. cm.) to two or three feet (.6 or .9m.), 

 alternating with beds of calcareous shale, the limestones 

 predominating. The limestones are usually dark gray in 

 color, compact, dense and tough except where they take 

 the form of intraformational congloiuerate. An occa- 

 sional layer of lighter gray softer limestone carries 

 many fragments of trilobites and brachiopods. Thick- 

 ness, 925 feet (281.9 m.) less 250 feet (76.2 m.) dupli- 

 cated by fault 675 205.8 



Fauna. — Near the summit of 3b the Syntrophia and Sym- 

 physurina faunules similar to those of the Stoddart-Dry 

 Creek section occur and they may also be found south- 

 west of the fault in the base of 3 (locality 2ie). 



Obolus cf. tetonensis Walcott 



Eoorthis putillus Walcott 



Syntrophia cf. calcifera Walcott 



Symphysurina 



Hystricurus 



cf . Isotcloides 

 4. The change between the base of No. 3 and the summit of 

 No. 4 is in the increased proportion of the shales and 

 the thinning of the layers of limestone. These shales 

 with their interbedded layers of limestone continue up 

 the canyon with an average dip of 70° to 80° west to 

 southwest. In the lower portion dirty gray argillaceous 

 shales predominate and have only a few thick (6 to 15 

 inches, 15.2 to 38.1 cm.) interbedded layers of hard, 

 finely semi-crystalline gray limestone with some intra- 

 formational conglomerate and near the base a few thin, 

 almost shaly, layers of compact, fine-grained, dove 

 colored limestone. 



